The present invention relates to a resin composition comprising poly(arylene sulfide) and a polyamide-imide, and particularly to a thermoplastic resin composition improved in compatibility, molding or forming ability, melt-flow properties and mechanical properties.
Poly(arylene sulfides) (hereinafter abbreviated as xe2x80x9cPASsxe2x80x9d) represented by poly(phenylene sulfide) (hereinafter abbreviated as xe2x80x9cPPSxe2x80x9d) are engineering plastics excellent in heat resistance, flame retardancy, chemical resistance, dimensional stability, mechanical properties and the like, and widely used electric and electronic parts, precision machinery parts, automotive parts, etc. However, the PASs have a comparatively low glass transition temperature and are greatly lowered in elastic modulus in a temperature range not lower than the glass transition temperature, so that their use has been limited in application fields of which high elastic modulus is required in a high temperature not lower than 100xc2x0 C.
On the other hand, polyamide-imides are engineering plastics excellent in heat resistance, mechanical properties, electrical properties, chemical resistance and the like. However, most of them are difficult to injection-mold, and they have been mainly used in application fields of varnishes, films and the like in the past.
Japanese Patent Application Laid-Open No. 306283/1994 discloses that resin compositions improved in melt moldability can be provided without impairing their heat resistance by blending an aromatic polyamide-imide copolymer having a repeating units of a specific structure with PPS. Since PAS and polyamide-imide are poor in compatibility with each other, however, it has been difficult to obtain a resin composition having sufficient mechanical properties by simply blending them.
It is an object of the present invention to provide a thermoplastic resin composition comprising a poly(arylene sulfide) and polyamide-imide, improved in compatibility between both resins and having excellent molding or forming ability, melt-flow properties and mechanical properties.
Another object of the present invention is to provide a thermoplastic resin composition by which both elastic modulus of a poly(arylene sulfide) at a high temperature and injection moldability of polyamide-imide are improved, and the flash length upon injection molding is reduced.
The present inventors have carried out an extensive investigation with a view toward overcoming the above-described problems involved in the prior art. As a result, it has been found that when a silane compound having a specific functional group is added to a resin component comprising a PAS and polyamide-imide, compatibility between both resins is markedly improved, thereby providing a thermoplastic resin composition having excellent molding or forming ability, melt-flow properties and mechanical properties.
When the silane compound having the specific functional group is added in the case where a fibrous or non-fibrous filler, other resins and the like are incorporated into the resin component comprising the PAS and polyamide-imide, the compatibility of the respective components including the additive component with one another is markedly improved to provide a thermoplastic resin excellent in various properties.
According to the thermoplastic resin compositions according to the present invention, the elastic modulus of the PAS at a high temperature and the injection moldability and extrudability of the polyamide-imide are improved while making the best use of the flame retardancy, chemical resistance, dimension stability and mechanical properties brought about by the PAS, and the heat resistance, mechanical strength, electrical properties and chemical resistance brought about by the polyamide-imide.
The present invention has been led to completion on the basis of these findings.
According to the present invention, there is thus provided a thermoplastic resin composition comprising 100 parts by weight of a resin component containing 40 to 99 wt. % of a poly(arylene sulfide) (A) and 1 to 60 wt. % of polyamide-imide (B), and 0.01 to 10 parts by weight of a silane compound (C) containing at least one functional group selected from the group consisting of amino, ureido, epoxy, isocyanate and mercapto groups.
Poly(arylene sulfide) (PAS):
The PAS useful in the practice of the present invention is an aromatic polymer having predominant repeating units of arylene sulfide represented by the formula [xe2x80x94Arxe2x80x94Sxe2x80x94] in which xe2x80x94Arxe2x80x94 means an arylene group. When the [xe2x80x94Arxe2x80x94Sxe2x80x94] is defined as 1 mole (basal mole), the PAS used in the present invention is a polymer containing this repeating unit in a proportion of generally at least 50 mol %, preferably at least 70 mol %, more preferably at least 90 mol %.
As examples of the arylene group, may be mentioned a p-phenylene group, a m-phenylene group, substituted phenylene groups (the substituent being preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group), a p,pxe2x80x2-diphenylene sulfone group, a p,pxe2x80x2-biphenylene group, a p,pxe2x80x2-diphenylenecarbonyl group and a naphthylene group. As the PAS, a polymer predominantly having only the same arylene groups may preferably be used. However, a copolymer having two or more different arylene groups may be used from the viewpoint of processability and heat resistance.
Among these PASs, PPS having predominant repeating units of p-phenylene sulfide is particularly preferred because it is excellent in processability and industrially available with ease. Besides the PPS, poly(arylene ketone sulfides), poly(arylene ketone ketone sulfide) and the like may be used. As specific examples of copolymers, may be mentioned random or block copolymers having repeating units of p-phenylene sulfide and repeating units of m-phenylene sulfide, random or block copolymers having repeating units of phenylene sulfide and repeating units of arylene ketone sulfide, random or block copolymers having repeating units of phenylene sulfide and repeating units of arylene ketone ketone sulfide, and random or block copolymers having repeating units of phenylene sulfide and repeating units of arylene sulfone sulfide. These PASs are preferably crystalline polymers. The PASs are preferably linear, or slightly branched or crosslinked polymers from the viewpoints of toughness and strength.
Such a PAS can be obtained in accordance with any publicly known process (for example, Japanese Patent Publication No. 33775/1988) in which an alkali metal sulfide and a dihalogen-substituted aromatic compound are subjected to a polymerization reaction in a polar solvent.
As examples of the alkali metal sulfide, may be mentioned lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide and cesium sulfide. Sodium sulfide formed by the reaction of NaSH and NaOH in the reaction system may also be used.
As examples of the dihalogen-substituted aromatic compound, may be mentioned p-dichlorobenzene, m-dichlorobenzene, 2,5-dichlorotoluene, p-dibromobenzene, 2,6-dichloronaphthalene, 1-methoxy-2,5-dichlorobenzene, 4,4xe2x80x2-dichlorobiphenyl, 3,5-dichlorobenzoic acid, p,pxe2x80x2-dichlorodiphenyl ether, 4,4xe2x80x2-dichlorodiphenyl sulfone, 4,4xe2x80x2-dichlorodiphenyl ether, 4,41-dichlorodiphenyl sulfone, 4,4xe2x80x2-dichlorodiphenyl sulfoxide and 4,4xe2x80x2-dichlorodiphenyl ketone. These compounds may be used either singly or in any combination thereof.
In order to introduce some branched or crosslinked structure into the PAS, a small amount of a polyhalogen-substituted aromatic compound having at least 3 halogen substituents per molecule may be used in combination. As preferable examples of the polyhalogen-substituted aromatic compounds, may be mentioned trihalogen-substituted aromatic compounds such as 1,2,3-trichlorobenzene, 1,2,3-tribromobenzene, 1,2,4-trichlorobenzene, 1,2,4-tribromobenzene, 1,3,5-trichlorobenzene, 1,3,5-tribromobenzene and 1,3-dichloro-5-brdmobenzene, and alkyl-substituted derivatives thereof. These compounds may be used either singly or in any combination thereof. Among these, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene and 1,2,3-trichlorobenzene are preferred from the viewpoints of profitability, reactivity, physical properties and the like.
As the polar solvent, aprotic organic amide solvents typified by N-alkylpyrrolidones such as N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), 1,3-dialkyl-2-imidazolidinones, tetraalkylureas, and hexaalkylphosphoric triamides are preferred because they have high stability in the reaction system and are easy to provide a high-molecular weight polymer.
The PAS used in the present invention is a polymer having a melt viscosity within a range of generally from 10 to 500 Paxc2x7s, preferably from 15 to 450 Paxc2x7s as measured at a temperature of 310xc2x0 C. and a shear rate of 1200/sec. If the melt viscosity of the PAS is too low, the mechanical properties of the resulting resin composition may possibly become insufficient. If the melt viscosity of the PAS is too high, the injection moldability and extrudability of the resulting resin composition may possibly become insufficient.
The PAS used in the present invention may be a polymer washed with water after completion of the polymerization. However, as the PAS, there may be preferably used a polymer treated with an aqueous solution containing an acid such as hydrochloric acid or acetic acid, or a mixed solution of water and an organic solvent, or a polymer subjected to a treatment with a solution of a salt formed of a weak acid and a weak base. In particular, the use of a PAS subjected to a washing treatment until its pH in a mixed solution of acetone/water prepared in a proportion of 1:2 comes to exhibit 8.0 or lower permits more improving the melt-flow properties and mechanical properties of the resulting resin composition.
The PAS used in the present invention is desirably in the form of particles having an average particle size of 100 xcexcm or greater. If the average particle size of the PAS is too small, the feed rate of the resulting thermoplastic resin composition is limited upon melt extrusion through an extruder, so that the resin composition has a possibility that the residence time of the resin composition in the extruder may become long to cause problems of deterioration of the resins, and the like. In addition, such a too small particle size is not desirable from the viewpoint of production efficiency.
A blending proportion of the PAS in the resin composition according to the present invention is 40 to 99 wt. %, preferably 45 to 95 wt. %, more preferably 50 to 85 wt. % based on the total weight of the PAS and the polyamide-imide. If the blending proportion of the PAS is too low, the mechanical strength of the resulting resin composition is deteriorated, and moreover, the injection moldability and extrudability thereof become insufficient. If the blending proportion of the PAS is too high, not only the effect to improve elastic modulus at a high temperature of at least 150xc2x0 C., but also the flash-inhibiting effect becomes insufficient.
Polyamide-imide:
The polyamide-imide (hereinafter may be referred to as xe2x80x9cPAIxe2x80x9d) useful in the practice of the present invention is generally a polymer produced from an aromatic tricarboxylic acid anhydride and an aromatic diamine and having a structural form alternately containing an imide group and an amide group.
The polyamide-imide is generally a polymer having, as a main unit structure, a unit represented by the formula (1): 
wherein Ar is a trivalent aromatic group containing at least one six-membered carbon ring, R is a bivalent aromatic or aliphatic group, and R1 is a hydrogen atom or an alkyl or phenyl group. A part (preferably less than 50 mol %, more preferably less than 30 mol %) of the imide bond in the formula (1) may remain as an amide bond.
As the polyamide-imide used in the present invention, is particularly preferred a polymer having the repeating unit represented by the formula (1) in a proportion of 100 mol %. However, a copolymer containing other repeating units in a proportion of preferably at most 50 mol %, more preferably at most 30 mol % may also be used.
As examples of other repeating units, may be mentioned repeating units represented by the following formulae (2) to (4). The copolymer may contain one or more of these repeating units. 
wherein Ar1 is a bivalent aromatic or aliphatic group containing at least one six-membered carbon ring group, and R is a bivalent aromatic or aliphatic group; 
wherein Ar2 is a tetravalent aromatic group containing at least one six-membered carbon ring group, and R is a bivalent aromatic or aliphatic group; and 
wherein Ar2 is a tetravalent aromatic group containing at least one six-membered carbon ring group, and R is a bivalent aromatic or aliphatic group.
In the formula (1), specific examples of the trivalent aromatic group (Ar) include groups represented by the formulae (5) to (8): 
Among these, the group of the formula (5) is preferred.
Specific examples of the bivalent aromatic or aliphatic group (R) include the formulae (9) to (35): 
Among these, are preferred the groups represented by the formulae (9), (10), (11), (16), (17), (20), (23), (24), (27) and (28), and the groups represented by the formulae (9), (10), (11), (20), (23) and (24) are particularly preferred, with the groups represented by the formulae (9), (11) and (20) being most preferred.
In the formula (2), specific examples of Ar1 include groups represented by the following formulae (36) to (41) in addition to the groups represented by the formulae (9), (10), (16), (17), (18), (19), (29), (30) and (35): 
In the formulae (3) and (4), specific examples of Ar2 include groups represented by the following formulae (42) and (43): 
In the respective repeating units represented by the formulae (1) to (4), different groups respectively corresponding to Ar, Ar1, Ar2 or R may be present in the polyamide-imide.
The polyamide-imide may be produced in accordance with a process such as (a) a process in which an aromatic tricarboxylic acid anhydride halide and a diamine are reacted with each other in a solvent (an acid chloride process), (b) a process in which an aromatic tricarboxylic acid anhydride and a diamine are reacted with each other in a solvent (a direct polycondensation process), or (c) a process in which an aromatic tricarboxylic acid anhydride and a diisocyanate are reacted with each other in a solvent (an isocyanate process).
In the acid chloride process (a), at least two aromatic tricarboxylic acid anhydride halides and diamines may be used. Further, a dicarboxylic acid dichloride or aromatic tetracarboxylic acid anhydride may be reacted as needed. The reaction can be conducted either by reacting the reactants in the presence or absence of a hydrogen halide acceptor such as triethylamine and sodium hydroxide in a polar solvent such as NMP or by reacting the reactants in the presence of the hydrogen halide acceptor likewise in a mixed solvent of an organic solvent (for example, acetone) miscible at least in part with water and water.
In the direct polycondensation process (b), at least two aromatic tricarboxylic acid anhydrides and diamines may be used. Further, a dicarboxylic acid or aromatic tetracarboxylic acid anhydride may be reacted as needed. The reaction can be conducted in the presence or absence of a dehydration catalyst in a polar solvent such as NMP or without using any solvent.
In the isocyanate process (c), at least two aromatic tricarboxylic acid anhydrides and diisocyanates may be used. Further, a dicarboxylic acid or aromatic tetracarboxylic acid anhydride may be reacted as needed. The reaction can be conducted in a polar solvent such as NMP or without using any solvent. In this process, effective means for efficiently conducting the reaction, controlling the structure of a polymer to be formed and modifying the molecular weight of the polymer are, for example, to conduct the reaction in a water content strictly controlled, to control the reaction temperature by multi stages to conduct a reaction for forming an imide group after completion of a reaction for forming an amide group, to use a catalyst as needed, and to conduct the reaction under the strict control of a molar ratio of the acid anhydride compound to the carboxylic acid compound.
In each of the above-described processes, a monofunctional compound such as a monocarboxylic acid such as benzoic acid; an acid chloride such as benzoyl chloride; a dicarboxylic acid anhydride such as succinic anhydride or naphthalenedicarboxylic acid anhydride; a monoisocyanate such as phenyl isocyanate; or a phenol may be used for the purpose of modifying the molecular weight of a polymer to be formed or controlling the structure of terminals of the polymer. The polymer obtained in accordance with any one of the above-described processes may be subjected to a heat treatment for converting the amido acid structure into an imido ring as needed.
When the polymerization reaction is conducted in a solution, the polyamide-imide used in the present invention is collected by treating a solution or slurry after completion of the reaction with an alcohol such as methanol, ethanol or isopropanol; a ketone such as acetone or methyl ethyl ketone; an aliphatic hydrocarbon such as hexane; or an aromatic hydrocarbon such as benzene or toluene to precipitate and wash a polymer formed. The polymer may be collected by directly removing the solvent by evaporation after completion of the polymerization reaction to deposit a polymer formed and then washing the polymer with the solvent described above. In the isocyanate process, the solvent may be concentrated to some extend after completion of the polymerization reaction and then removed under reduced pressure by an extruder or the like.
The polyamide-imide used in the present invention may be a polymer produced in accordance with any process of the processes (a), (b) and (c). In the case where the resulting resin composition is used in injection molding or extrusion, however, the polyamide-imide prepared by the isocyanate process (c) may preferably be used from the viewpoints of easy structure control and molecular weight modification of the polymer formed. The polyamide-imide used in the present invention has a reduced viscosity of generally 0.10 to 1.50 dl/g, preferably 0.12 to 1.00 dl/g, more preferably 0.15 to 0.80 dl/g as determined by viscosity measurement at 30xc2x0 C. and a polymer concentration of 1 g/dl in dimethylformamide.
A blending proportion of the polyamide-imide in the resin composition is 1 to 60 wt. %, preferably 5 to 55 wt. %, more preferably 15 to 50 wt. % based on the total weight of the PAS and the polyamide-imide. If the blending proportion of the polyamide-imide is too low, the effect to improve elastic modulus at a high temperature becomes insufficient. If the blending proportion of the PAS is too high, the mechanical strength of the resulting resin composition is deteriorated, and moreover, the injection moldability and extrudability thereof become insufficient.
Silane Compound:
The functional group-containing silane compound useful in the practice of the present invention is a silane compound containing at least one functional group selected from the group consisting of amino, ureido, epoxy, isocyanate and mercapto groups in its molecule. The functional group-containing silane compound may be generally a silane compound containing any one of these functional groups in its molecule. In some cases, it may be a silane compound containing two or more of these functional groups in its molecule. The silane compound used in the present invention is generally an alkoxysilane or halosilane containing such a functional group as described above in its molecule.
Specific examples of the functional group-containing silane compound include amino group-containing silane compounds such as xcex3-aminopropyltrimethoxysilane, xcex3-aminopropyltriethoxysilane, xcex3-aminopropylmethyldimethoxysilane, xcex3-aminopropylethyldiethoxysilane, xcex3-aminopropylmethyldiethoxysilane, N-(xcex2-aminoethyl)-xcex3-aminopropyltrimethoxysilane, N-(xcex2-aminoethyl)-xcex3-aminopropylmethyldimethoxysilane, xcex3-phenyl-xcex3-aminopropyltrimethoxysilane and xcex3-ureidopropyltriethoxysilane; ureido group-containing silane compounds such as xcex3-ureidopropyltrimethoxysilane, xcex3-ureidopropylmethyltrimethoxysilane, xcex3-ureidopropyltriethoxysilane, xcex3-ureidopropylmethyltriethoxysilane and xcex3-(2-ureidoethyl)-aminopropyltrimethoxysilane; epoxy group-containing silane compounds such as xcex3-glycidoxypropyltrimethoxysilane, xcex3-glycidoxypropyldimethylmethoxysilane, xcex3-glycidoxypropyltriethoxysilane, xcex3-glycidoxypropylmethyldiethoxysilane, xcex2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and xcex2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; isocyanate group-containing silane compounds such as xcex3-isocyanatopropyltrimethoxysilane, xcex3-isocyanatopropylmethyldimethoxysilane, xcex3-isocyanatopropyltriethoxysilane, xcex3-isocyanatopropylmethyldiethoxysilane, xcex3-isocyanatopropylethyldimethoxysilane, xcex3-isocyanatopropylethyldiethoxysilane and xcex3-isocyanatopropyltrichlorosilane; and mercapto group-containing silane compounds such as xcex3-mercaptopropylmethyldimethoxysilane, xcex3-mercaptopropyltriethoxysilane, xcex3-mercaptopropylmethyldimethoxysilane, xcex3-mercaptopropylmethyldiethoxysilane, xcex2-mercaptoethyltrimethoxysilane, xcex2-mercaptoethyltriethoxysilane and xcex2-mercaptoethyldimethoxysilane.
These functional group-containing silane compounds are preferably alkoxysilane compounds or halosilane compounds containing at least one functional group selected from the group consisting of amino, ureido, epoxy, isocyanate and mercapto groups. The functional group-containing alkoxysilane compounds are preferably functional group-substituted alkyl.alkoxysilane compounds having a functional group-substituted alkyl group and an alkoxy group. The functional group-substituted alkyl.alkoxysilane compounds are preferably silane compounds in which the functional group-substituted alkyl group has 1 to 4 carbon atoms, and the alkoxy group has 1 to 4 carbon atoms, namely, xe2x80x9cfunctional group-substituted (C1-C4)alkyl.(C1-C4)alkoxysilane compoundsxe2x80x9d. As examples of such functional group-substituted alkyl.alkoxysilane compounds, may be mentioned xcex3-aminopropyl.trialkoxysilane compounds, xcex3-glycidoxypropyl.trialkoxysilanes, xcex3-mercaptopropyl.trialkoxysilanes, xcex3-isocyanatopropyl.trialkoxysilanes and xcex3-ureidopropyl trialkoxysilanes as those excellent in the effect of addition thereof and easy to be available.
These functional group-containing silane compounds may be used either singly or in any combination thereof. A compounding proportion of the functional group-containing silane compounds is 0.01 to 10 parts by weight, preferably 0.05 to 8 parts by weight, more preferably 0.1 to 5 parts by weight based on 100 parts by weight of the total amount of the PAS and the polyamide-imide. If the compounding proportion of these functional group-containing silane compounds is too low, the mechanical property-improving effect by the addition thereof becomes little. If the proportion is too high on the other hand, the resulting resin composition tends to generate gases in the course of molding or forming and processing, resulting in a molded or formed product liable to cause voids. In many cases, the functional group-containing silane compound can exhibit a sufficient effect in an amount of about 0.3 to 2 parts by weight per 100 parts by weight of the resin component. In the case where a great amount of a filler is blended, or the like, however, it is preferable to compound the functional group-containing silane compound in a relatively great amount into the resin component for achieving sufficient compatibility. The functional group-containing silane compound can exhibit its compatibility-improving effect in an amount of generally about 0.1 to 2 wt. %, preferably about 0.3 to 1 wt. % based on the total weight of the resin composition containing the resin component and various kinds of additives.
Organic Amide Compound:
When a small amount of an organic amide compound is added to the thermoplastic resin composition according to the present invention, the melt-flow properties and mechanical properties of the composition can be enhanced.
Examples of the organic amide compound include amides such as N,N-dimethylformamide and N,N-dimethylacetamide; N-alkylpyrrolidones or N-cycloalkylpyrrolidones such as N-methyl-2-pyrrolidone and N-cyclohexyl-2-pyrrolidone; N-alkylcaprolactams or N-cycloalkylcaprolactams such as N-methyl-xcex5-caprolactam and N-cyclohexylcaprolactam; caprolactams such as xcex5-caprolactam; N,N-dialkylimidazolidinones such as 1,3-dimethyl-2-imidazolidinone; tetraalkylureas such as tetramethylurea; and hexaalkylphosphoric triamides such as hexamethylphosphoric triamide. These organic amide compounds may be used either singly or in any combination thereof.
Among the organic amide compounds, the N-alkylpyrrolidones, N-cycloalkylpyrrolidones, N-alkylcaprolactams, N-cycloalkylcaprolactams, caprolactams and N,N-dialkylimidazolidinones are preferred, with the N-alkylpyrrolidones, caprolactams and N,N-dialkylimidazolidinones being particularly preferred.
The organic amide compound is compounded in a proportion of generally 0.01 to 10 parts by weight, preferably 0.1 to 8 parts by weight, more preferably 0.5 to 5 parts by weight per 100 parts by weight of the total amount of the PAS and the polyamide-imide. If the compounding proportion of the organic amide compound is too low, the effects of improving the melt-flow properties and mechanical properties become little. If the compounding proportion is too high, the strength of the resulting resin composition is lowered, and there is a possibility that unfavorable phenomena such as bleeding may be caused.
Other Thermoplastic Resins:
Into the resin compositions according to the present invention, may be added other thermoplastic resins within limits not impeding the objects of the present invention. The other thermoplastic resins are preferably thermoplastic resins stable at a high temperature.
As examples of the other thermoplastic resins, may be mentioned aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate; fluorocarbon resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene/hexafluoropropylene copolymers, tetrafluoroethylene/perfluoroalkyl vinyl ether copolymers, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride/hexafluoropropylene copolymers, propylene/tetrafluoroethylene copolymers, vinylidene fluoride/chlorotrifluoroethylene copolymers and ethylene/hexafluoropropylene copolymers; polyolefins such as polyethylene and polypropylene; and polyacetal, polystyrene, polyamide, polycarbonate, polyphenylene ether, polyalkyl acrylate, ABS resins, polyvinyl chloride, liquid crystalline polyesters, poly(ether ether ketone), poly(ether ketone), polysulfone and poly(ether sulfone).
These thermoplastic resins may be used either singly or in any combination thereof. In many cases, however, the other thermoplastic resins are used in a small amount within limits not impeding the various properties of the resin composition of the PAS and the polyamide-imide. A preferable compounding proportion of the other thermoplastic resins is at most 50 parts by weight, more preferably at most 30 parts by weight per 100 parts by weight of the total amount of the PAS and the polyamide-imide.
Filler:
Into the thermoplastic resin compositions according to the present invention, may be compounded various kinds of fillers as needed. As examples of the fillers, may be mentioned fibrous fillers, such as inorganic fibrous materials such as glass fiber, carbon fiber, asbestos fiber, silica fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber and potassium titanate fiber (whisker); metallic fibrous materials such as stainless steel, aluminum, titanium, copper and brass; and high-melting organic fibrous materials (for example, Aramid fiber) such as polyamide, fluorocarbon resins, polyester resins and acrylic resins.
As examples of non-fibrous fillers, may be mentioned particulate, powdery or flaky fillers such as mica, silica, talc, alumina, kaolin, calcium sulfate, calcium carbonate, titanium oxide, magnetic powders (for example, ferrite), clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate and barium sulfate. Conductive fillers such as conductive carbon black may also be used as filler.
These fillers may be used either singly or in any combination thereof. The fillers may be treated with greige goods or surface-treating agents as needed. Examples of the greige goods or surface-treating agents ainclude functional compounds such as epoxy compounds, isocyanate compounds and titanate compounds. These compounds may be used for subjecting fillers to a surface treatment or collecting treatment in advance, or added at the same time upon the preparation of a resin composition.
In the thermoplastic resin compositions according to the present invention, as needed, these fillers may be compounded within a range of generally 0 to 800 parts by weight, preferably 0 to 500 parts by weight, more preferably 0 to 300 parts by weight per 100 parts by weight of the resin component. The compounding proportion of the fillers varies according to the intended functions of the resulting thermoplastic resin composition. When the thermoplastic resin composition is used as a magnetic material by compounding, for example, magnetic powder such as ferrite therein, the magnetic powder is generally compounded in a proportion of about 100 to 800 parts by weight per 100 parts by weight of the resin component. When the thermoplastic resin composition is used as a heat-conductive material by compounding a heat-conductive filler such as alumina, the filler is generally compounded in a proportion of about 50 to 300 parts by weight per 100 parts by weight of the resin component. In the case of electrically conductive carbon black, the carbon black is generally compounded in a proportion of about 1 to 100 parts by weight per 100 parts by weight of the resin component according to the desired volume resistivity of the resulting resin composition.
In particular, the compounding of an inorganic fibrous filler such as glass fiber permits the provision of a resin composition excellent in mechanical properties such as tensile strength, flexural strength, flexural modulus and maximum strain in bending. When the inorganic fibrous filler is compounded for improving these mechanical properties, it is compounded in a proportion of preferably 1 to 300 parts by weight, more preferably 5 to 150 parts by weight, particularly preferably 10 to 100 parts by weight per 100 parts by weight of the resin component.
The glass fiber-filled thermoplastic resin composition is suitable for use as an insulating material in a wide variety of fields. The carbon fiber-filled thermoplastic resin composition is suitable for use as an electrically conductive material or sliding material. The carbon black-filled thermoplastic resin composition is suitable for use as an electrically conductive material. The Aramid fiber-, PTFE- or potassium titanate whisker-filled thermoplastic resin composition is suitable for use as a sliding material. The alumina-filled thermoplastic resin composition is suitable for use as a heat-conductive material. The silica-filled thermoplastic resin composition is suitable for use as a sealing material. The ferrite-filled thermoplastic resin composition is suitable for use as a magnetic material.
At least two fibrous filler, at least two non-fibrous fillers, or at least one fibrous filler and at least one non-fibrous filler may be used in combination. Further, at least one other thermoplastic resin and at least one filler (fibrous filler and/or non-fibrous filler) may also be used in combination. Specific examples thereof include the combined use of at least one fibrous filler (for example, glass fiber) and electrically conductive carbon black, and the combined use of PTFE and potassium titanate fiber.
Other Additives:
Into the resin compositions according to the present invention, may be suitably added, for example, resin-modifying agents such as ethyleneglycidyl methacrylate, lubricants such as pentaerythritol tetrastearate, antioxidants, thermosetting resins, ultraviolet absorbents, nucleating agents such as boron nitride, flame retardants; colorants such as dyes and pigments, and the like as other additives than the above-described additives.
Thermoplastic Resin Composition:
The thermoplastic resin compositions according to the present invention can be prepared by equipment and methods generally used in the preparation of synthetic resin compositions. The resin composition can be prepared in accordance with, for example, a process comprising premixing the individual raw components by means of a Henschel mixer or tumbler, adding a filler such as glass fiber, as needed, to further continue the mixing, kneading the resultant mixture in a single-screw or twin-screw extruder and then extruding the kneaded mixture into pellets for molding. There may also be used a process in which part of the necessary components are mixed as a masterbatch, and the mixture is mixed with the remaining components, or a process in which part of raw materials used are ground for the purpose of enhancing the dispersibility of the individual components, thereby making the particle sizes of the components uniform, and they are mixed and melt-extruded.
The thermoplastic resin compositions according to the present invention can be molded or formed into sheets, films, tubes or other molded or formed products by applying the conventional melt processing techniques such as injection molding and extrusion to the compositions. The molded or formed products are excellent in stiffness at a temperature not lower than 150xc2x0 C., flame retardancy, heat resistance, chemical resistance, dimensional stability, mechanical properties, and the like and can be used in a wide variety of fields of which these properties are required.